<template>
    <div class="todo-footer" v-show="total">
        <label>
        <!-- <input type="checkbox" :checked="isAll" @change="checkAll"/> -->
        <input type="checkbox" v-model="isAll"/>
        </label>
        <span>
        <span>已完成{{ doneTotal }}</span> / 全部{{total}}
        </span>
        <button class="btn btn-danger" @click="clearAllTodo">清除已完成任务</button>
    </div>
</template>

<script>
    export default{
        name: 'MyFooter',
        props:['cars'],
        computed:{
          total(){
              return this.cars.length
          },
          doneTotal(){
            // const x = this.cars.reduce((pre, current)=>{
            //   return pre+(current.done?1:0)
            // },0)
            // return x
            return this.cars.reduce((pre, current)=>pre+(current.done?1:0),0)
          },
          //计算属性如果要修改就不能写成下面的简写形式
          // isAll(){
          //     return this.total === this.doneTotal && this.total > 0
          // }
          isAll:{
            get(){
              return this.total === this.doneTotal && this.total > 0
            },
            set(value){
              // console.log(value)
              this.$emit('checkAll',value)
            }
          },
        },
        methods:{
            clearAllTodo(){
              this.$emit('clearAll')
            }
          }
    }
</script>

<style scoped>
  /*footer*/
  .todo-footer {
    height: 40px;
    line-height: 40px;
    padding-left: 6px;
    margin-top: 5px;
  }

  .todo-footer label {
    display: inline-block;
    margin-right: 20px;
    cursor: pointer;
  }

  .todo-footer label input {
    position: relative;
    top: -1px;
    vertical-align: middle;
    margin-right: 5px;
  }

  .todo-footer button {
    float: right;
    margin-top: 5px;
  }
</style>